How long can ice and water shield be exposed before it is covered?
Short answer. It depends on the product: many self-adhered membranes allow about 30 to 120 days of sunlight exposure before they must be covered, and the exact limit is printed on the data sheet. UV breaks down the surface and adhesive over time, and exceeding the limit can void the product warranty, so the best practice is to cover it as soon as possible.
What the published limits look like
Exposure limits vary widely. Among common products, one film-surfaced leak barrier lists up to 60 days, a widely used standard membrane lists up to 90 days, and a high temperature version of that same membrane lists up to 120 days. Some products allow only about 30 days. Always check the exact product, because two rolls that look alike can have very different limits.
Why the limit exists
- Ultraviolet light degrades the top film or surfacing and the asphalt beneath.
- Heat softens the adhesive, which can cause sagging on steep slopes.
- Dust and pollen settle on exposed laps and edges, weakening the bond of anything applied over them.
- Foot traffic and debris scuff and tear an exposed membrane.
Georgia planning tips
- Summer sun and heat use up exposure time faster in practical terms, so do not plan on the maximum.
- After a big storm, materials can be backordered. If the roof is dried in with membrane while waiting for shingles, track the days.
- Membrane is not a substitute for a properly secured emergency tarp over a damaged roof, and policies expect reasonable steps to prevent further damage; see emergency tarp and mitigation duty.
If the limit is exceeded
Inspect the surface for cracking, chalking or lifted laps. Damaged areas should be replaced or covered with new membrane before roofing goes on, and the product warranty may no longer apply. More in ice and water shield in Georgia.